/*
 * Copyright (C) 2011-2014 GUIGUI Simon, fyhertz@gmail.com
 *
 * This file is part of libstreaming (https://github.com/fyhertz/libstreaming)
 *
 * Spydroid is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This source code is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this source code; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package net.majorkernelpanic.streaming.rtp;

import java.io.IOException;

import android.util.Log;

/**
 * RFC 4629.
 * <p>
 * H.263 Streaming over RTP.
 * <p>
 * Must be fed with an InputStream containing H.263 frames.
 * The stream must start with mpeg4 or 3gpp header, it will be skipped.
 */
public class H263Packetizer extends AbstractPacketizer implements Runnable {

    public final static String TAG = "H263Packetizer";
    private Statistics stats = new Statistics();

    private Thread t;

    public H263Packetizer() {
        super();
        socket.setClockFrequency(90000);
    }

    public void start() {
        if (t == null) {
            t = new Thread(this);
            t.start();
        }
    }

    public void stop() {
        if (t != null) {
            try {
                is.close();
            } catch (IOException ignore) {
            }
            t.interrupt();
            try {
                t.join();
            } catch (InterruptedException e) {
            }
            t = null;
        }
    }

    public void run() {
        long time, duration = 0;
        int i = 0, j = 0, tr;
        boolean firstFragment = true;
        byte[] nextBuffer;
        stats.reset();

        try {
            while (!Thread.interrupted()) {

                if (j == 0) buffer = socket.requestBuffer();
                socket.updateTimestamp(ts);

                // Each packet we send has a two byte long header (See section 5.1 of RFC 4629)
                buffer[rtphl] = 0;
                buffer[rtphl + 1] = 0;

                time = System.nanoTime();
                if (fill(rtphl + j + 2, MAX_PACKET_SIZE - rtphl - j - 2) < 0) return;
                duration += System.nanoTime() - time;
                j = 0;
                // Each h263 frame starts with: 0000 0000 0000 0000 1000 00??
                // Here we search where the next frame begins in the bit stream
                for (i = rtphl + 2; i < MAX_PACKET_SIZE - 1; i++) {
                    if (buffer[i] == 0 && buffer[i + 1] == 0 && (buffer[i + 2] & 0xFC) == 0x80) {
                        j = i;
                        break;
                    }
                }
                // Parse temporal reference
                tr = (buffer[i + 2] & 0x03) << 6 | (buffer[i + 3] & 0xFF) >> 2;
                //Log.d(TAG,"j: "+j+" buffer: "+printBuffer(rtphl, rtphl+5)+" tr: "+tr);
                if (firstFragment) {
                    // This is the first fragment of the frame -> header is set to 0x0400
                    buffer[rtphl] = 4;
                    firstFragment = false;
                } else {
                    buffer[rtphl] = 0;
                }
                if (j > 0) {
                    // We have found the end of the frame
                    stats.push(duration);
                    ts += stats.average();
                    duration = 0;
                    //Log.d(TAG,"End of frame ! duration: "+stats.average());
                    // The last fragment of a frame has to be marked
                    socket.markNextPacket();
                    send(j);
                    nextBuffer = socket.requestBuffer();
                    System.arraycopy(buffer, j + 2, nextBuffer, rtphl + 2, MAX_PACKET_SIZE - j - 2);
                    buffer = nextBuffer;
                    j = MAX_PACKET_SIZE - j - 2;
                    firstFragment = true;
                } else {
                    // We have not found the beginning of another frame
                    // The whole packet is a fragment of a frame
                    send(MAX_PACKET_SIZE);
                }
            }
        } catch (IOException e) {
        } catch (InterruptedException e) {
        }

        Log.d(TAG, "H263 Packetizer stopped !");

    }

    private int fill(int offset, int length) throws IOException {
        int sum = 0, len;

        while (sum < length) {
            len = is.read(buffer, offset + sum, length - sum);
            if (len < 0) {
                throw new IOException("End of stream");
            } else sum += len;
        }

        return sum;

    }

}
